Note: Descriptions are shown in the official language in which they were submitted.
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BALL INSERTION DEVICE FOR USE IN OIL AND GAS WELLS
FIELD OF INVENTION
The present invention relates to a ball insertion device for use in oil and
gas wells.
BACKGROUND OF THE INVENTION
Oil and gas wells are typically subjected to fracturing or other stimulation
procedures by isolating zones of interest in the wellbore by use of packers
and the like.
Thereafter, a treatment fluid or fracturing fluid is forced into the isolated
zone at an
elevated treatment pressure. In a typical fracturing procedure for a cased
wellbore, for
example, the casing of the well is first perforated to allow oil and/or gas to
flow into the
wellbore. Thereafter, a fracturing fluid is then pumped into the wellbore and
through the
perforations into the formation. Such treatment opens and/or enlarges drainage
channels
in the formation, enhancing the producing ability of the well. For open holes
that are not
cased, stimulation is carried out directly in the zone intervals without the
need for
perforating casing.
Frequently, a series of packers in a packer arrangement may be inserted into
the
wellbore, wherein the packers are located at intervals for isolating one zone
from an
adjacent zone. To selectively engage a packer, a ball ("frac ball') is
typically introduced
into the wellbore so as to block fluid flow through the packer, which creates
an isolated
zone up-hole from the blocked packer so that a fluid treatment or stimulation
may be
performed on that isolated interval. Once the previously isolated (lower) zone
has been
stimulated, a subsequent ball is dropped to block off a subsequent packer that
is
positioned up-hole from the previously blocked packer, so as to create another
isolated
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zone up-hole of the second blocked packer. This isolated zone is then
fractured or
treated. The process is continued until all of the desired zones have been
stimulated
and/or fractured. Typically the balls range in diameter from a smallest
diameter ball,
which is suitable for blocking fluid flow through the most downholc packer, to
the largest
diameter ball, which is suitable for blocking fluid flow through the most up-
hole packer.
Equipment for fracturing, such as a "frac head," is typically provided at the
surface of a well so that fracturing operations may be conducted. The frac
head includes
fluid connections for introducing fracturing fluids, which may include
proppants and like,
into the wellbore, and ultimately into the formation during the fracturing
process. There
are various prior art systems that have been employed for introducing the frac
balls into a
wellbore. Some are very complex and involve a complex arrangement of various
valves
and fittings that are operated so as to introduce the frac balls into the
wellbore. Such
complexity may lead to additional costs, operator errors, down time due to
maintenance
of the complex arrangement of valves and fittings and/or failure of one or
more of the
pieces of equipment.
The present application is directed to a novel ball insertion device for use
in oil
and gas wells that may eliminate or at least minimize some of the problems
noted above.
BRIEF DESCRIPTION OF THE INVENTION
The following presents a simplified summary of the invention in order to
provide
a basic understanding of some aspects of the invention. This summary is not an
exhaustive overview of the invention. It is not intended to identify key or
critical
elements of the invention or to delineate the scope of the invention. Its sole
purpose is to
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present some concepts in a simplified form as a prelude to the more detailed
description
that is discussed later.
The present application is directed to a novel ball insertion device for use
in oil
and gas wells. In one illustrative embodiment, the ball inserter device
comprises, among
other things, a body having a ball insertion opening and a ball drop opening
defined in the
body, wherein the ball drop opening intersects the ball insertion opening, a
ball inserter
piston that is attached to the body and an inserter cavity isolation valve
coupled to the
body wherein the valve element, when closed, blocks the ball insertion opening
and
partially defines an inserter cavity between the inserter isolation valve and
the ball
inserter piston and a pressure relief valve coupled to the body that is in
fluid
communication with the inserter cavity. In this example, the device also
comprises a ball
input device coupled to the body that includes a plug, a removable cap and an
opening
that is axially aligned with the ball drop opening.
One illustrative method disclosed herein includes, among other things, closing
at
least a lower master valve so as to isolate a ball inserter device positioned
vertically
between an upper master valve and a lower master valve from pressure within a
well
bore, opening a relief valve so as to relieve pressure within an inserter
cavity that is
located in a body of the ball inserter device between a closed inserter cavity
isolation
valve and a ball inserter piston that is coupled to the body, after relieving
the pressure
within the inserter cavity, removing a plug from a ball input device so as to
allow
communication with a ball drop opening defined in the body, wherein the ball
drop
opening intersects a ball insertion opening defined in the body and inserting
a ball
through the ball input device so as to position the ball within the inserter
cavity between
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the ball inserter piston and the closed inserter cavity isolation valve. In
this example, the
method further comprises, with the inserter cavity isolation valve in its
closed position,
coupling the removable plug to the ball input device, after coupling the
removable plug to
the ball input device, opening the inserter cavity isolation valve so as to
allow the inserted
ball to be moved through the open inserter cavity isolation valve and the ball
insertion
opening defined in the body, actuating the ball inserter piston from a
retracted position to
an extended position so as to move the ball through the open inserter cavity
isolation
valve and the ball insertion opening and into the well bore, after inserting
the ball into the
well bore, actuating the ball inserter piston so as to cause it to return
toward the retracted
position, closing the inserter isolation valve so as to block the ball
insertion opening and,
after closing the inserter isolation valve so as to block the ball insertion
opening, opening
the upper master valve and the lower master valve.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be described with the accompanying drawings, which
represent a schematic but not limiting its scope:
Figures 1A-1C depict one illustrative example of a novel ball insertion device
for
use in oil and gas wells disclosed herein; and
Figures 2A-2H depict one illustrative operational sequence of an illustrative
ball
insertion device for use in oil and gas wells disclosed herein.
While the subject matter disclosed herein is susceptible to various
modifications
and alternative forms, specific embodiments thereof have been shown by way of
example
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in the drawings and are herein described in detail. It should be understood,
however, that
the description herein of specific embodiments is not intended to limit the
invention to the
particular forms disclosed, but on the contrary, the intention is to cover all
modifications,
equivalents, and alternatives falling within the spirit and scope of the
invention as defined
by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
Various illustrative embodiments of the invention are described below. In the
interest of clarity, not all features of an actual implementation are
described in this
specification. It will of course be appreciated that in the development of any
such actual
embodiment, numerous implementation-specific decisions must be made to achieve
the
developers' specific goals, such as compliance with system-related and
business-related
constraints, which will vary from one implementation to another. Moreover, it
will be
appreciated that such a development effort might be complex and time-
consuming, but
would nevertheless be a routine undertaking for those of ordinary skill in the
art having
the benefit of this disclosure.
The present subject matter will now be described with reference to the
attached
figures. Various structures, systems and devices are schematically depicted in
the
drawings for purposes of explanation only and so as to not obscure the present
disclosure
with details that arc well known to those skilled in the art. Nevertheless,
the attached
drawings are included to describe and explain illustrative examples of the
present
disclosure. The words and phrases used herein should be understood and
interpreted to
have a meaning consistent with the understanding of those words and phrases by
those
skilled in the relevant art. No special definition of a term or phrase, i.e.,
a definition that
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is different from the ordinary and customary meaning as understood by those
skilled in
the art, is intended to be implied by consistent usage of the term or phrase
herein. To the
extent that a term or phrase is intended to have a special meaning, i.e., a
meaning other
than that understood by skilled artisans, such a special definition will be
expressly set
forth in the specification in a definitional manner that directly and
unequivocally provides
the special definition for the term or phrase.
One illustrative system 100 that includes an illustrative example of a ball
insertion
device 22 for use in oil and gas wells disclosed herein is depicted in Figures
IA-1C. The
ball insertion device 22 will be disclosed in the context of using the ball
insertion device
22 for a well fracturing application. However, as will be appreciated by those
skilled in
the art after a complete reading of the present application, the novel ball
insertion device
22 disclosed herein may be employed in a variety of applications as it relates
to
operations performed on oil and gas wells.
Figure 1A is a partial cross-sectional elevation view depicting one
illustrative
example of a system 100 where one embodiment of an illustrative ball insertion
device 22
may be employed. As shown therein, the system 100 is comprised of a plurality
of pieces
of equipment positioned above an illustrative wellhead 10. The wellhead 10
provides
access to a wellbore (not shown) (cased or un-cased) in an earthen formation.
In the
depicted example, the system is comprised of several items of equipment
positioned
above the wellhead 10: a tubing head 12, a lower master valve 14, a flow
outlet valve 16,
an upper master valve 18 and a frac head 20. In the depicted example, a spool
(e.g., a tee)
21 is positioned between the lower and upper master valves 14, 18, and one
illustrative
example of a ball inserter device 22 disclosed herein is removably coupled to
the spool 21
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by a plurality of bolts. A bore 25 is defined in the spool 21 and it is
axially aligned with
other bores (not shown) in the various pieces of equipment above and below the
spool 21,
and the bore 25 is in fluid communication with the wellbore that extends into
the
formation. In the depicted example, the ball inserter device 22 is coupled to
the spool 21.
However, in other applications, the spool 21 may be omitted and the ball
inserter device
22 may be coupled to or formed integrally with another item of equipment
positioned
above the wellhead 10. Different sized spools 21 may also be provided with
different
bores 25 therein for different sized wells, wherein the same ball inserter
device 22 is a
universal device that may be used with each of the different sized spools.
Figure 1B is a cross-sectional plan view taken through the ball inserter
device 22
and the spool 21 where indicated in Figure 1A. Figure 1C is a cross-sectional
elevation
view taken through the ball inserter device 22, the spool 21, and the
lower/upper master
valves 14, 18. As shown in Figures 1B-1C, the illustrative example of the ball
inserter
device 22 disclosed herein is generally comprised of an inserter body 30
having an
inserter cavity 33 defined therein, an inserter cavity isolation valve 26, a
ball inserter
piston 28, an inserter cavity relief valve 31 and a ball input device 32 (see
Figure 1C). In
the depicted example, each of the inserter cavity isolation valve 26, the ball
inserter piston
28, the inserter cavity relief valve 31 and the ball input device 32 are
removably coupled
to the inserter body 30 via bolted connections. However, as noted above, in
some
applications, the inserter body 30 may be formed integral with the spool 21 or
the spool
21 may be omitted and the inserter body 30 may be attached to or formed
integral with
another item of equipment positioned above the wellhead 10.
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In the depicted example, a plurality of drilled openings are formed in the
inserter
body 30: a ball insertion opening 41, a pressure relief opening 43, and a ball
drop opening
45 (see Figure 1C). As described more fully below, an inserter cavity 33 is
defined, at
least in part, by a portion of the ball insertion opening 41 between the
inserter cavity
isolation valve 26 and the ball inserter piston 28. The ball insertion opening
41 is in fluid
communication with the bore 25 defined in the spool 21 and defines a constant
diameter
opening from the piston 28 to the bore 25. The pressure relief opening 43
provides fluid
communication between the inserter cavity 33 and the inserter cavity relief
valve 31. The
ball drop opening 45 is in fluid communication with the inserter cavity 33
(i.e., the ball
insertion opening 41). The ball drop opening 45 provides the conduit by which
frac balls
(not shown) will be inserted into the inserter cavity 33. In general, the size
of the
openings 41, 43, 45 may vary depending upon the particular application. The
ball
insertion opening 41 and the ball drop opening 45 will normally have the same
internal
diameter and they may be sized to accommodate the largest ball that will be
inserted into
a range of wells where the ball inserter device 22 is expected to be deployed,
e.g., they
may have an internal diameter of about 4 inches in one illustrative
embodiment. Of
course, balls having a lesser diameter than the inside diameter of the ball
insertion
opening 41 and ball drop opening 45 may be inserted into a well using the
novel ball
inserter device 22 disclosed herein, e.g., 2 inch diameter balls may be
inserted using a ball
inserter device 22 with a ball insertion opening 41 having a diameter of 4
inches. In one
example, with the ball insertion opening 41 and the ball drop opening 45 both
having an
internal diameter of 4 inches, the ball inserter device 22 disclosed herein
may be
employed to insert frac balls having diameters that fall within the range of
about 0.5 ¨ 4
inches. The pressure relief opening 43 may be of any diameter sufficient for
performing
its pressure relief function as frac balls will not be inserted through the
pressure relief
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opening 43. In the depicted example, an opening 21A is defined in the spool
21. The
opening 21A is in fluid communication with the bore 25 in the spool 21. The
opening
21A in the spool 21 has a diameter that is equal to a diameter of the ball
insertion opening
41 formed in the body 30.
The inserter cavity isolation valve 26 may be any type of valve suitable for
performing its isolation function when it is in a closed position and allowing
a frac ball to
pass through the ball insertion opening 41 and the inserter cavity isolation
valve 26 when
it is in an open position. In one illustrative example, the inserter cavity
isolation valve 26
may be a gate valve or a ball valve. The inserter cavity isolation valve 26
may be
actuated in any desired manner, e.g., manually, hydraulically or electrically.
In the
example depicted in the drawings, the inserter cavity isolation valve 26 is a
gate valve
that may be manually actuated by turning a wheel 39. In the depicted example,
the
inserter cavity isolation valve 26 is provided with pressure balancing means
34 for
reducing the actuating forces needed to open or close the inserter cavity
isolation valve
26. Such pressure balancing means are well known to those skilled in the art.
As
depicted in Figure 1B, the gate 47 of the inserter cavity isolation valve 26
is in a closed
position where, in combination with the seats 48, the gate 47 acts to block
the ball
insertion opening 41 and isolate the inserter cavity 33 from pressure within
the wellbore
25. However, the inserter cavity isolation valve 26 is also adapted to be
actuated such
that an opening 47A in the gate 47 is aligned with the ball insertion opening
41 so as to
thereby allow a frac ball to pass from the ball inserter cavity 33 through the
opening 47A
in the gate 47 and down the ball insertion opening 41 into the well bore 25,
as described
more fully below.
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The ball inserter piston 28 may be a pneumatic or hydraulic double-acting
piston.
The ball inserter piston 28 has a ball engagement attachment 38 that is
removably coupled
to the rod of the piston 28. The piston 28 is coupled to the body 30 such that
the rod of
the piston 28 is axially aligned with the ball insertion opening 41. In one
example, the
ball engagement attachment 38 may be made of a relatively hard material, such
as steel,
and it may have a substantially planar engagement face 38A that is adapted to
engage a
frac ball during the ball insertion process. The ball inserter piston 28
should have a
sufficient stroke such the engagement face 38A of the engagement attachment 38
may be
positioned at least a portion of the way into the bore 25 to insure that the
ball has been
properly inserted. Of course, stroke of the ball inserter piston 28 (in
absolute length
terms) may vary depending upon the particular application and the size of the
components
of the system 100.
With reference to Figure 1B, the illustrative inserter cavity relief valve 31
disclosed herein may be any type of valve suitable for performing its venting
function as
described herein. In one illustrative example, the inserter cavity relief
valve 31may be a
plug valve. fhe inserter cavity relief valve 31 is removably coupled to an
adapter 35 via
a coupling 36. A seal 37 is provided between the inserter cavity relief valve
31 and the
adapter 35. The adapter 35 is coupled to the inserter body 30 by a plurality
of bolts. A
coupling 47 is also coupled to the inserter cavity relief valve 31 so as to
provide
connection to piping (not shown). In the depicted example, the inserter cavity
relief valve
31 is oriented such that an opening 35A in the adapter 35 is substantially
horizontal. The
inserter cavity relief valve 31 is in fluid communication with the inserter
cavity 33 via the
pressure relief opening 43 and the opening 35A. In general, with the inserter
cavity
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isolation valve 26 in the closed position, the inserter cavity relief valve 31
may be opened
to vent and relieve pressure within the inserter cavity 33.
With reference to Figure 1C, the illustrative ball input device 32 disclosed
herein
is comprised of a removable plug 42, a removable cap 44 and an adapter 40. The
cap 44
is removably coupled to the adapter 40. The adapter 40 is coupled to the
inserter body 30
by a plurality of bolts. A seal 43 is provided between the plug 42 and the
adapter 40. In
the depicted example, the ball inserter device 22 is oriented such that the
opening 40A in
the adapter 40 is substantially vertical and axially aligned with the ball
drop opening 45.
In one embodiment, the size of the opening 40A should at least be equal to the
size of the
ball insertion opening 41 and the ball drop opening 45. With the inserter
cavity isolation
valve 26 in the closed position, and after venting the inserter cavity 33 (by
actuating the
inserter cavity relief valve 31), the cap 42 may be removed and the plug 42
may then be
removed. With the plug 42 removed, a frac ball may be inserted or dropped
through the
opening 40A into the ball drop opening 45 and thus the inserter cavity 33 in
front of the
engagement face 38A of the engagement attachment 38 attached to the ball
inserter piston
28. The overall height of the ball input device 32 (from the top of the plug
42 to the body
30) should be kept to a minimum so as to avoid damage to frac balls as they
are dropped
into the inserter cavity 33.
Figures 2A-2H depict one illustrative operational sequence of the illustrative
ball
insertion device 22 disclosed herein for use during fracturing operations
performed on an
oil/gas well. Each of the Figures 2A-2H contain a plan view of the device
disclosed
herein in the top portion of the drawing and an elevation view of the device
disclosed
herein in the bottom portion of the drawing.
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As shown in Figure 2A, the first major operation is to insure that inserter
cavity 33
is isolated from well bore pressure. As depicted in Figure 2A, the inserter
cavity isolation
valve 26 and the inserter cavity relief valve 31 will normally both be in the
closed
position during normal wellbore operations and only opened as described below
as part of
the frac ball insertion process. After insuring that the inserter cavity
isolation valve 26
and the inserter cavity relief valve 31 are both closed, and as depicted in
Figure 2A, at
least the lower master valve 14 is closed. In some applications, both of the
lower and
upper master valves 14, 18 will be closed. The ball inserter piston 28 will
also be in its
fully retracted position as this process begins.
Next, as shown in Figure 2B, with the inserter cavity isolation valve 26 in
its
closed position, the inserter cavity relief valve 31 is opened to vent or
relieve pressure
within the inserter cavity 33 (behind the closed inserter cavity isolation
valve 26). This
insures that the inserter cavity 33 is at atmospheric pressure.
Next, as shown in Figure 2C, with the ball inserter piston 28 in its fully
retracted
position, and the inserter cavity isolation valve 26 in its closed position,
the plug 42 of the
ball input device 32 is removed. Thereafter, a frac ball 50 is dropped or
inserted into the
inserter cavity 33 (via the opening 40A and the ball drop opening 45) to a
position in
front of the ball engagement attachment 38 of the piston 28.
Next, as shown in Figure 2D, with the inserter cavity isolation valve 26 in
its
closed position, the plug 42 of the ball input device 32 is replaced and the
inserter cavity
relief valve 31 is closed.
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Next, as shown in Figures 2E-2F, the inserter cavity isolation valve 26 is
opened,
and the piston 28 is actuated so as to force the ball 50 down the ball
insertion opening 41
toward the bore 25. Figure 2F depicts the device after the piston 28 has been
fully
extended so as to position the ball 50 within the bore 25. The ball 50
initially falls within
the bore 25 due to the force of gravity. At some point later, pressure may be
applied to
force the ball 50 down into the well.
Figure 2G depicts the device after the piston 28 was fully retracted and after
the
inserter cavity isolation valve 26 was moved to its closed position. Note that
at this point
the ball 50 is positioned on the closed lower master valve 14.
Figure 2H depicts the device after the lower and upper master valves 14, 18
have
been opened. At this point normal wellbore operations may proceed.
As will be appreciated by one skilled in the art after a complete reading of
the
present application, the novel system and method disclosed herein may provide
several
distinct advantages. For example, using the system disclosed herein, the frac
balls 50 are
isolated from the fracking fluid until such time as they are deployed into the
wellbore.
Additionally, using the system disclosed herein, the frac balls 50 are
inserted into the frac
fluid at a location below the flow tee or frac head 20 that is positioned
above the upper
master valve 18 during fracking operations. By inserting the frac balls 50 at
this location,
the reliability of the frac ball deployment process is increased.
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The particular embodiments disclosed above are illustrative only, as the
invention
may be modified and practiced in different but equivalent manners apparent to
those skilled
in the art having the benefit of the teachings herein. For example, the
process steps set forth
above may be performed in a different order. Furthermore, no limitations are
intended to the
details of construction or design herein shown, other than as described in the
claims below.
It is therefore evident that the particular embodiments disclosed above may be
altered or
modified and all such variations are considered within the scope and spirit of
the invention.
Note that the use of terms, such as "first," "second," "third" or "fourth" to
describe various
processes or structures in this specification and in the attached claims is
only used as a
shorthand reference to such steps/structures and does not necessarily imply
that such
steps/structures are performed/formed in that ordered sequence. Of course,
depending upon
the exact claim language, an ordered sequence of such processes may or may not
be
required.
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